Automatic pathway and waypoint generation and navigation method

ABSTRACT

A navigation system for use in a luminal network of a patient, such as the airways, that is able to analyze a three-dimensional model of the luminal network and automatically determine a pathway from an entry point to a designated target. The system further automatically assigns waypoints along the determined pathway in order to assist a physician in navigating a probe to the designated target.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. patent application Ser. No.13/544,468, filed on Jul. 9, 2012, which claims priority to U.S. Pat.No. 8,218,846 filed May 14, 2009, which claims priority to U.S.Provisional Patent Application No. 61/053,523, filed May 15, 2008, eachof which is entitled Automatic Pathway And Waypoint Generation AndNavigation Method and is hereby incorporated by reference.

BACKGROUND

Breakthrough technology has emerged which allows the navigation of acatheter tip through a tortuous channel, such as those found in thepulmonary system, to a predetermined target. This technology comparesthe real-time movement of a locatable guide (LG) against athree-dimensional digital map of the targeted area of the body (forpurposes of explanation, the pulmonary airways of the lungs will be usedhereinafter, though one skilled in the art will realize the presentinvention could be used in any body cavity or system: circulatory,digestive, pulmonary, to name a few).

Such technology is described in U.S. Pat. Nos. 6,188,355; 6,226,543;6,558,333; 6,574,498; 6,593,884; 6,615,155; 6,702,780; 6,711,429;6,833,814; 6,974,788; and 6,996,430, all to Gilboa or Gilboa et al.;U.S. Published Applications Pub. Nos. 2002/0193686; 2003/0074011;2003/0216639; 2004/0249267 to either Gilboa or Gilboa et al; as well asU.S. patent application Ser. No. 11/939,537 to Averbuch et al. All ofthese references are incorporated herein in their entireties.

Using this technology begins with recording a plurality of images of theapplicable portion of the patient, for example, the lungs. These imagesare often recorded using CT technology. CT images are two-dimensionalslices of a portion of the patient. After taking several, parallelimages, the images may be “assembled” by a computer to form a virtualthree-dimensional model of the lungs.

The physician then takes this virtual model and, using the softwaresupplied with the navigation system, plans a path to the target.Planning the path to the target involves creating a patient file andselecting and saving various waypoints along the path to the target. Thephysician also selects and saves various registration points used by thesoftware to register the virtual model to the actual patient in theupcoming procedure.

Typically, there is only one path that leads to the target, unless thetarget is very large. In the airways and vasculature of the body, thebody lumina do not split and then rejoin downstream. The branches of atree provide a good analogy: for any given leaf on a tree, there is onlyone combination of branches that lead to that leaf. Hence, the step ofpathway planning is a time-consuming step that would be avoided ifautomated.

Additionally, the present systems provide guidance to the target, butnot necessarily to the waypoints along the way. Instead of focusing onthe target, it would be advantageous to provide navigation guidance toeach of the intermittent waypoints, thereby treating each successivewaypoint as a target, then, after the waypoint is reached, changing thetarget to the next waypoint.

SUMMARY

In view of the foregoing, one aspect of the present invention provides asystem and method for automatically planning a pathway from an entrypoint in a patient to a target through a luminal network.

Another aspect of the present invention automatically generates thevarious waypoints between a starting point and the target.

Another aspect of the present invention provides a system and method forproviding navigational cues to a target via the plurality of waypoints.The cues are provided in such a manner that the next waypoint in a pathis automatically detected and treated as a destination. Navigationalcues are provided to that waypoint until it is reached. The system thenselects the next waypoint along the path and provides navigational cuesto that waypoint. This continues until the actual target is reached.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart describing a general step of a method of thepresent invention;

FIG. 2 is a flowchart describing a general step of a method of thepresent invention;

FIG. 3 is a flowchart describing a general step of a method of thepresent invention;

FIG. 4 is a user interface of an embodiment of the system of the presentinvention; and

FIG. 5 is a user interface of an embodiment of the system of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Generally, the present invention includes a system and method forconstructing, selecting and presenting pathway(s) to a target locationwithin an anatomical luminal network in a patient. The present inventionis particularly, but not exclusively, suited for guiding and navigatinga probe through the bronchial airways of the lungs. The presentinvention includes a preoperative and an operative component. Thepreoperative component is conducted prior to navigation and can becategorized as “Pathway Planning.” The operative component is conductedduring navigation and can be categorized as “Navigation.”

Pathway Planning

The pathway planning phase includes three general steps, each of whichis described in more detail below. The first step involves using asoftware graphical interface for generating and viewing athree-dimensional model of the bronchial airway tree (“BT”). The secondstep involves using the software graphical interface for selection of apathway on the BT, either automatically, semi-automatically, ormanually, if desired. The third step involves an automatic segmentationof the pathway(s) into a set of waypoints along the path that can bevisualized on a display. It is to be understood that the airways arebeing used herein as an example of a branched luminal anatomicalnetwork. Hence, the term “BT” is being used in a general sense torepresent any such luminal network, and not to be construed to onlyrefer to a bronchial tree, despite that the initials “BT” may not applyto other networks.

First Step—BT Generation

Referring now to FIG. 1, there is shown a flowchart describing the firststep—using a software graphical interface for generating and viewing aBT. At 20, the first step begins with importing CT scan images,preferably in a DICOM format, into the software. The data may beimported into the software using any data transfer media, including butnot limited to CDs, memory cards, network connections, etc.

At 22 the software processes the CT scans and assembles them into athree-dimensional CT volume by arranging the scans in the order theywere taken and spacing them apart according to the setting on the CTwhen they were taken. The software may perform a data fill function tocreate a seamless three-dimensional model.

At 24, the software uses the newly-constructed CT volume to generate athree-dimensional map, or BT, of the airways. The three dimensional mapcan either be skeletonized, such that each airway is represented as aline, or it may be include airways having dimensions representative oftheir respective diameters. Preferably, when the BT is being generated,the airways are marked with an airflow direction (inhalation,exhalation, or separate arrows for each) for later use during thepathway generation step. It is envisioned that this step is optional.The CT volume may be used as it is.

At 26, the software displays a representation of the three-dimensionalmap on a user interface, such as a computer monitor.

Second Step—Pathway Selection

Referring now to FIG. 2, there is shown a flowchart describing thesecond step—using the software graphical interface for selection of apathway on the BT. At 40, the second step begins with a determination,by the software, of an appropriate pathway to a selected target.

In one embodiment, the software includes an algorithm that does this bybeginning at the selected target and following lumina back to the entrypoint. Using the airways as an example, the target is first selected.The software then selects a point in the airways nearest the target. Ifthe point closest to the target is in an airway segment that is betweenbranches, the software has to choose between two directional choices. Ifthe airways of the BT were marked with airflow direction, the softwaremoves in the opposite direction of the arrows, thereby automaticallygenerating a pathway to the entry point.

Alternatively, the pathway to the target may be determined using airwaydiameter. Moving toward the entry point (the trachea) results in anincreased airway diameter while moving distally results in a decreasedairway diameter. Hence, the software could choose to move in thedirection of increased airway diameter. If the point closes to thetarget is in an airway segment that includes one or more branches, thechoices are more numerous but the following the path of the greatestincrease in airway diameter will still result in the correct path to theentry point.

Though unlikely, in the event that an incorrect path is taken, thesoftware would eventually detect an inevitable decrease in diameter, ifthis is the case, the software would automatically abort that path andrevert to the last decision-making point. The algorithm will resume,blocking off the incorrect path as an option.

At 42, after the pathway has been determined, or concurrently with thepathway determination, the suggested pathway is displayed for userreview. Preferably, the entire BT will be displayed with the suggestedpathway highlighted in some fashion. The user will have zoom and panfunctions for customizing the display.

At 44, the user is given the opportunity to edit and confirm thepathway. There may be reasons an alternative pathway is desirable. Forexample, though the targeted lesion is closest to a particular airway,there may be an artery or a lobe division between the selected airwayand the target. Hence, it is important to provide the user with editingability.

Third Step—Waypoint Selection

Referring now to FIG. 3, there is shown a flowchart describing the thirdstep—using the software to automatically generate waypoints. At 60, thethird step begins by designating each of the decision making points from40 of step 2 as waypoints. This may happen concurrently with 40. Eachtime the software, while navigating backwards toward the trachea, waspresented with navigational choices, the user navigating toward thetarget will necessarily also be presented with choices. Hence, it islogical to designate those decision-making points as waypoints along thepath to the target.

At 62, the waypoints appear on the suggested pathway, and may be labeledin such a way as to distinguish them from each other. For example, thewaypoints may be numbered, beginning at 1, in the order that theyappear. Preferably, the waypoints are positioned just downstream of eachbifurcation, instead of at the bifurcation. In this way, providingnavigation directions to the waypoint results in the probe beingpositioned in the appropriate airway once the waypoint has been reached.Hence, the physician can begin navigation to the next waypoint by simplyadvancing the probe without being concerned about advancing down anincorrect airway.

At 64, the user is given the opportunity to edit the waypoints. It isunderstood that the second and third steps may occur concurrently. Ifthe user is editing the pathway to the target, the user will also beselecting alternative waypoints, as one in the art will realize.

Fly-Through Feature

In addition to the editing features described above, the softwarepresents a “fly-through” feature that presents the user with theopportunity to view the user interface as it would appear from start tofinish if the procedure was performed as planned. A preferred embodimentof one view the user interface is shown in FIG. 4.

The interface 80 is divided into four quadrants, 82, 84, 86 and 88. Theupper-left quadrant 82 is a lateral view of the CT volume of the lungs,i.e. as though looking parallel to the spine of the patient. Thelower-left quadrant 84 is a birds-eye view of the CT volume of thelungs. The upper-right quadrant 86 is a side view of the CT volume ofthe lungs. The lower-right quadrant 88 is a three-dimensionalperspective view inside a virtual airway of the BT. Cross-hairs 90 spanover all of the quadrants to show the present location of the LG. Thecross-hairs 90 in quadrant 88 are shown in a perspective format.

Navigation

The heading “Navigation” refers to the processes occurring during theactual procedure. Referring now to FIG. 5, there is shown a userinterface 100 that assists the user in navigating to the target. Thisview of the user interface 100 includes four quadrants 102, 104, 106,and 108. The images shown in each quadrant are preferably customizable.Hence, any of the aforementioned views from interface 80 may bedisplayed. However, pertinent to the navigation discussion is the viewshown in the lower-right quadrant 108.

Quadrant 108 is shown as displaying an LG steering indicator. Thedestination 110 appears as a circle which floats over the quadrant 108and moves when the LG is turned. The destination 110 represents the nextwaypoint to which the user is navigating, or the final destination(targeted lesion) in the event that the last waypoint has been passed.

When the distal tip of the LG is pointing directly at the destination110, the destination 110 appears in the center of the circle 112. If theLG is not pointing directly at the destination 110, the destination 110is located in a representative location in or out of the circle 112. Forexample, if the LG is pointing down and right of the destination 110 inthe body (in other words, the destination 110 is above and left of wherethe LG is pointing), the destination 110 on the display in quadrant 108will appear above and left of the center of the circle 112. If the LG isdeflected away from the destination 110 far enough, the destination 110may not even appear in the quadrant 108. For this reason, a guide arrow114 appears somewhere on the circle 112. The guide arrow 114 tells theuser which direction the LG must be deflected to align the tip with thedestination 110.

Although the invention has been described in terms of particularembodiments and applications, one of ordinary skill in the art, in lightof this teaching, can generate additional embodiments and modificationswithout departing from the spirit of or exceeding the scope of theclaimed invention. Accordingly, it is to be understood that the drawingsand descriptions herein are proffered by way of example to facilitatecomprehension of the invention and should not be construed to limit thescope thereof.

We claim:
 1. A method of providing a pathway through a luminal networkof a patient from an entry point to a target, comprising: selecting atarget in a luminal network; and determining a pathway through theluminal network from a selected entry point to the target by beginningat the target and following lumina back to the entry point.
 2. Themethod of claim 1, further comprising providing a map of the luminalnetwork, wherein the target is selected on the map.
 3. The methodaccording to claim 2, wherein providing the map includes constructing athree-dimensional model of the luminal network by assembling a pluralityof CT scans of the luminal network.
 4. The method of claim 1, whereinfollowing lumina back to the entry point includes calculating a paththrough the lumina based upon luminal diameter.
 5. The method of claim1, wherein following lumina back to the entry point includes followingan airflow direction.
 6. The method of claim 1, wherein determining thepathway further includes assigning at least one waypoint along thepathway.
 7. The method of claim 6, wherein assigning the at least onewaypoint includes detecting an airway intersection and designating apoint spaced apart from the intersection as a waypoint.
 8. A method ofaccessing a target in a luminal network, comprising: selecting a targetin a luminal network; determining a pathway through the luminal networkfrom a selected entry point to the target by beginning at the target andfollowing lumina back to the entry point; inserting a guide into theluminal network; and advancing the guide through the luminal network tothe target following the determined pathway.
 9. The method of claim 8,further comprising providing a three-dimensional model of the luminalnetwork, wherein the target is selected on the three-dimensional model.10. The method of claim 9, further comprising displaying arepresentation of the three-dimensional model on a user interface. 11.The method of claim 10, further comprising displaying a representationof the determined pathway through the three-dimensional model on theuser interface.
 12. The method of claim 11, wherein advancing the guidethrough the luminal network includes following the representation of thedetermined pathway displayed on the user interface.
 13. The method ofclaim 8, wherein following lumina back to the entry point includescalculating a path through the lumina based upon luminal diameter. 14.The method of claim 8, wherein following lumina back to the entry pointincludes following an airflow direction.
 15. The method of claim 8,wherein determining the pathway further includes assigning at least onewaypoint along the pathway.
 16. The method of claim 15, whereinassigning the at least one waypoint includes detecting an airwayintersection and designating a point spaced apart from the intersectionas a waypoint.
 17. A method of providing a pathway through a luminalnetwork of a patient from an entry point to a target, comprising:providing an algorithm that automatically determines a pathway through aluminal network from a selected entry point to a target by beginning atthe target and following lumina back to the entry point.
 18. The methodof claim 17, wherein following lumina back to the entry point includesautomatically calculating a path through the lumina based upon luminaldiameter.
 19. The method of claim 17, wherein following lumina back tothe entry point includes automatically calculating a path through thelumina following an airflow direction.
 20. The method of claim 17,wherein automatically determining the pathway further includesautomatically assigning at least one waypoint along the pathway.